For example, in a gear support shaft of a transmission of a vehicle including an engine, various types of rolling bearings, such as a deep groove ball bearing and an angular contact ball bearing, are widely used.
A rolling bearing of this type mainly includes an inner race having a radially outer surface in which an inner raceway surface is formed, an outer race being arranged on an outer side of the inner race, and having a radially inner surface in which an outer raceway surface is formed, a plurality of rolling elements interposed between the inner raceway surface of the inner race and the outer raceway surface of the outer race in a freely rollable manner, and a retainer arranged between the inner race and the outer race, for retaining the rolling elements equiangularly. Anyone of the inner race and the outer race is mounted to a stationary part such as a housing, and another one of the inner race and the outer race is mounted to a rotary part such as a rotation shaft.
For use of the rolling bearing of this type, there have been proposed rolling bearings of various types, such as a rolling bearing including means for accelerating an inflow of lubricant into an inside of the bearing (for example, see Patent Literature 1), and a rolling bearing including means for restricting the inflow of the lubricant into the inside of the bearing (for example, see Patent Literature 2).
The rolling bearing disclosed in Patent Literature 1 has the following structure. Specifically, races formed of an outer race and an inner race are arranged coaxially, and a plurality of rolling elements are inserted between the races. An annular sealing member is arranged so as to seal an internal space defined by the outer race, the inner race, and the rolling elements, and the sealing member includes an introducing portion having a hole formed therein so as to communicate an outside of the bearing and the inside of the bearing.
In this rolling bearing, using rotation of the sealing member along with rotation of the inner race and the outer race, the lubricant that is present outside the bearing is drawn into the inside of the bearing through the hole of the introducing portion of the sealing member. With this configuration, without separately providing a special lubricating device for pumping the lubricant or separately forming an oil-feeding hole in a track surface, the lubricant can be introduced into the inside of the bearing. Thus, satisfactory rotation performance is ensured at the time of high-speed rotation.
Further, the rolling bearing disclosed in Patent Literature 2 has the following structure. Specifically, narrow guide gaps are formed between the retainer and the inner race and between the retainer and the outer race, and a lubricant-inflow-side end surface of the retainer is formed into an inclined surface. Further, a radially inner surface of the retainer is formed into an inclined surface.
In this rolling bearing, the narrow guide gaps are formed between the retainer and the inner race and between the retainer and the outer race, and the lubricant-inflow-side end surface of the retainer is formed into the inclined surface, and thus the lubricant is prevented from being excessively drawn into the inside of the bearing. Further, the radially inner surface of the retainer is formed into the inclined surface, and thus the lubricant, which excessively flows into the inside of the bearing, is actively discharged to an outside of the bearing.